New year, same old stories. Milan and Juventus winning, Antonio Di Natale scoring and yet another manager hurtling towards the sack at Palermo. Bortolo Mutti might feel that two games is an insufficient basis on which to be judged, but he will also know better than to presume such logic applies in the kangaroo court of Maurizio Zamparini. When Mutti accepted the owner's invitation to replace Devis Mangia in December, he became the club's third manager already this season.

Mutti, indeed, is Zamparini's 22nd appointment in nine and a half years at Palermo. If there is a certain romance to the idea that Mutti could be the man he was looking for all along – the one who got away, having been in charge at Palermo when Zamparini bought the club in 2002 only to move on when his contract was not renewed by the new regime – then we must remember that the owner is still a man very much on the rebound after splitting from the manager he called his "wife", Delio Rossi, in June.

Rossi, lest we forget, had secured some of the best results in the club's history – the 65 points, 18 wins and 59 goals scored in 2009-10 each representing an all-time high for Palermo in Serie A. It is safe to assume that Zamparini will be rather less impressed with the contribution made by Mutti to his team's record books on Sunday: a first home defeat to Napoli in 43 years.

"I dreamed that we won 1-0," hurrahed Zamparini in a radio interview during the buildup to the game, but he awoke to a face full of cold water as Goran Pandev opened the scoring for Napoli with a balletic turn and finish 10 minutes before half-time. The goal had arrived just at the point when Palermo looked most threatening – Fabrizio Miccoli dragging a shot wide from the edge of the box before new signing Franco Vázquez chipped over the bar when put through one-on-one.

Worse was to come, Edinson Cavani – who had started the move for Pandev's goal by releasing Walter Gargano down the right – curling a delightful effort into the top corner from outside the box before Marek Hamsik made it three from an acute angle. Miccoli achieved some measure of consolation with a wonderful looping header, but the result still felt emphatic. Having won their opening six home games this season – scoring 16 goals along the way – this was a second consecutive defeat for Palermo at the Stadio Renzo Barbera (albeit the previous one came before Mutti's appointment).

It might have made things worse that Cavani – who joined Napoli from Palermo in 2010 – should play such a prominent role, had the player not handled himself so graciously. Sections of the home crowd had heckled their former idol on both this and last year's visit, but they rose to applaud on Sunday as he declined to celebrate.

"I was moved," he said later as reporters sought confirmation that they had seen the hint of a tear in his eyes. "I respect my former fans and I was happy at their applause after the goal." Quite the contrast then, with Napoli's last win here – back in 1969 – when José Altafini sparked a pitch invasion with a rather less salutary gesture to the crowd.

Seeing a former hero achieving such success elsewhere is a familiar reality for Palermo fans, Zamparini moving players even more rapidly than he does managers (with rather more positive outcomes for the balance sheet). The home supporters had voiced their fear of relegation before full time, yet in many ways it is remarkable that they should find themselves ninth at this stage after a summer which saw not only Rossi depart but also Javier Pastore, the starting goalkeeper Salvatore Sirigu and midfielder Antonio Nocerino, to name but a few.

Vázquez, a trequartista who began training with the club little more than a week ago following his move from Argentina's Belgrano, was signed to challenge Josip Ilicic – suspended on Sunday – for Pastore's place and despite that miss the signs were encouraging. Mutti's decision to withdraw both him and Francesco Della Rocca at half-time appeared with hindsight to have been a significant mistake.

Mutti acknowledged as much, saying: "I hoped [Afriyie] Acquah and [Edgar] Alvarez could give us more thrust on the wings, but it never arrived. Instead the exact opposite happened, and we wound up getting confused. The team no longer had the right rhythm and then the second goal demoralised us."

Zamparini made no immediate comment, though it can be taken as read that one will be forthcoming before too long. To assume he wouldn't sack a manager after two games is incorrect – that's precisely the number of games Stefano Pioli got at the start of this season, dismissed after drawing both legs of a Europa League tie with FC Thun but exiting the competition on away goals – though there is no sense that Mutti's position is under threat quite yet. But when you are dealing with the self-described "manager-eater", it is only ever a matter of time.

Talking points

• If Napoli's win represented a break from historical precedent then theirs was still not the real surprise of the round. Siena had not won in seven games – indeed, they hadn't scored since 20 November – coming into their home fixture against Lazio, while the Biancocelesti were unbeaten away from the Stadio Olimpico – having collected five wins and two draws on their travels. With Siena's fans staging a protest against their team's president, Massimo Mezzaroma, before kick-off, the stage hardly seemed set for what was to come: a 4-0 victory.

"Absurd", was Corriere dello Sport's verdict, while the Lazio manager, Edy Reja, was at a loss to explain what had gone on. "How can you explain what happened here," he asked. "I can only say one thing: I don't think this is the real Lazio." Perhaps not, but this was a third game in a row without a win. With reports of disharmony in the dressing room and certain players avoiding punishment after returning late from their winter break, it is perhaps not an eagle that can be seen circling the Stadio Olimpico at present, but rather the first of the vultures.

• Then again, Lazio are not the only team whose winter schedule has come under scrutiny. Inter were widely criticised for allowing their players to stay out on holiday until 2 January – four days later than either Milan or Juventus – yet they looked all the fresher for it as they tore Parma apart on the way to a 5-0 victory. As Andrea Elefante noted in Gazzetta dello Sport, "it was one of those matches in which you have to ask yourself where the gifts from your opponents end and your own merits begin", but even before the break Inter's improving form under Claudio Ranieri could not be ignored. This was a fifth win in a row, and a seventh in eight games. They have conceded just three goals over the latter spell.

• While Inter celebrated, the Parma president, Tommaso Ghirardi, pondered his next move, and the manager, Franco Colomba, is expected to lose his job in the next 24 hours. Roberto Donadoni and Gigi Del Neri are being reported as the leading candidates for the job.

• If Inter have found their form at an important time ahead of next week's Derby della Madonnina, then Milan continue to look every bit the irresistible juggernaut as they keep step with Juventus at the top of the table. A trip to Atalanta hardly represented the gentlest of starts to the new year – Stefano Colantuono's team were unbeaten at home until this weekend – yet the Rossoneri were deserving winners, with goals from Zlatan Ibrahimovic and Kevin-Prince Boateng. How grateful will they be, over the next few months, for the latter's decision to retire from international football ahead of the Africa Cup of Nations?

• Juventus were also victorious, of course, at Lecce – the enthusiasm generated by their season so far reflected by the 2,000 supporters who turned up at, and were eventually allowed in to watch the end of, a training session on the day before the game. There was some hostility from the supporters too, however, towards the team's latest addition. "[Marco] Borriello: a mercenary without honour and dignity," read a banner displayed in the away supporters' end at the Stadio Via del Mare.